Maryland's Occupational Safety and Health Division is heading the investigation into the May 23 accident that killed Carroll "Star" Dexter Wills, 57, of Frederick, MD.

Wills and another construction worker were inside the structure, which was under construction at Westfield Montgomery Mall, in Bethesda, MD, when it caved in shortly after 2 p.m., as shoppers looked on in shock.

Wills was pronounced dead at the scene. The other worker, whose identity has not been released, is reported in critical condition.

WBAL-TV

Carroll "Star" Dexter Wills (left) was pronounced dead at the scene. At right, a worker trapped in the debris for more than four hours gives a thumbs-up before being flown to an area hospital.

"It was loud," said shopper Bany Alavi. "I would say like a really loud bomb, just a really loud bang. I didn’t know ‘Did a bomb go off?’"

The collapsed section, about 40 feet long, occurred between the second and third levels of the garage, about 500 feet from a Macy's department store.

Delicate Rescue

Rescue personnel worked for more than four hours to stabilize the structure before they were able to free the second worker, said Assistant Montgomery County Fire and Rescue Chief Scott Graham.

“In the middle of the extraction, we did notice some shifting of the concrete,” Graham told reporters.

As a result, they paused the rescue and, with help from structural engineers, altered their approach. More than 100 people were involved in the rescue attempt, said Graham.

Whiting-Turner

The project's general contractor was Whiting-Turner. It was not immediately known if that company or a subcontractor was working on the scene at the time.

The other worker was conscious and alert when rescued, even giving a thumbs-up to reporters at the scene before being flown to the Maryland Shock Trauma Center in Baltimore. His condition has been reported variously as critical and serious.

Rebecca Kresge, who identified herself on Twitter as a relative of the victim, said he was severely injured and told the Washington Post that he would require several surgeries on his arm. Kresge said her relative was "alert and very strong" and was "doing just fine considering what happened."

Contractor Undisclosed

The men's employer still has not been publicly identified.

A Montgomery County official identified the general contractor on the project as Baltimore-based Whiting-Turner, which typically ranks among the top domestic general building contractors as reported by Engineering News Record (ENR).

It was not known, however, if Whiting-Turner or a subcontractor was working on the site when the accident occurred. The company has not commented and did not respond to a request for comment.

Emergency crews worked for more than four hours to rescue one of the workers. The other perished at the scene.

Diane Schwartz Jones, director of Montgomery’s Department of Permitting Services, told the Washington Post that her office was reviewing the project's many permits and permit applications and could not immediately say whether any problems or citations had been issued during construction.

“This project has been around for a long time,” Jones told the newspaper. “There are a lot of permits for that site.”

The parking garage, just outside Washington, D.C., was in the midst of a major three-phase redevelopment project that involved putting a 16-screen movie theater on top of the parking garage.

Montgomery County approved the project in 2005.

A check of federal Occupational Safety and Health Administration records showed no inspections or citations on the garage project in the last three years.